A PRELIMINARY REPORT ON CLAYS OF FLORIDA 197


 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent.
 950*C. 0.37 35.6 Red.
 1010 35.8 Red.
 1040 35.6 Red.
 1070 36.0 Red.
 1100 0.47 34.8 Red.
 1130 33.8 Red.
 1160 33.8 Red.
 1190 33.7 Red.
 1220 0.08 33.6 Red.
 1250 33.7 Red.
 1280 33.4 Red.
 1310 0.24 33.6 Red.


 PUTNAM COUNTY

 Putnam County lies in the St. Johns River valley in the northeastern part of the State. The western part of the county is underlain by the Alum Bluff formation. Pliocene and Pleistocene sands and marls underlie the eastern part of the county. Flood-plain clay deposits are common along the St. Johns River. Lacustrine deposits are widely scattered over the county. The sedimentary kaolin occurs at several points in the southwestern part of the county. These are described in Chapter IX.
 Several brick plants have formerly been operated in the region around Palatka. The clays were all St. Jolns River flood-plain clays.
 A clay formerly worked by the Utica Brick and Tile Company at Rice Creek Station may be used for common brick, face brick, hollow blocks, fireproofing, and drain tile. This deposit adjoins the Atlantic Coast Line Railroad and is located about 100 yards south of the station. Its physical properties are:


 Physical Properties of Rice Creek Station Clay (Lab. No. o-4t2).
 Plasticity, judged by feel........... Excellent.
 W ater of plasticity................. 24.20%
 Pore w ater ........................ 0.50%
 Shrinkage water .................. 23.70%
 Linear air shrinkage............... 7.7 %
 Volume fire shrinkage.............. 30.5 %
 Modulus of rupture, average........ 776.3 pounds per square inch.
 Slaking test ....................... 6 hours.